Oscillation damping device free from radiation for electric lines



J. w. HOFMANN OSCILLATION D AMPING DEVICE FREE FROM RADIATION FOR ELEC TRIC LINES June 24, 1930.

Filed Aug. 17. 1927 Patented June '24, 1930 UNITED. STATES PATENT OFFICE J'OHANN'ES WILHELI HOFHANN, KOTZSCHENBRODA, NEAR DRESDEN,

. GERMANY OBCILLATIOI T DAIPING DEHICE FREE FROM'RADIATION FOR ELECTRIC LIKES Application fled August 17; 1927, Serial No. 218,564, and in Germany February 11, 1027.

. that the line-cable prematurely breaks down at its points of fixation to stay or supporting clamps or terminals. The causes of said premature destructioncan be found in that the oscillations of the line-cable are brought to rest at the stay or supporting-points without any change and the bending loads maintained thereby in the line-cable cause a fatigue of the material; and the ruptures 20 will take place after a relatively short time, if .the oscillations are reinforced by the phenomena of resonance. However, means have heretofore been found and used 'for damping the oscillations or preventing the phenomena of resonance. A known means of this kind consists in weights which are suspended on the line near the fixation or supporting points, said weights being yieldin ly connected by s rings with the line. If, s0 th 11, oscillations ta e place in the line the weights are also moved. However, the freuency of oscillation of the weights is diferent from the frequency of oscillation of the line as a consequence of the yielding coniiection with the hue, whereby the waves of oscillation are damped within the line. The oscillations of the yieldingly arranged weights act in opposition to the oscillations of the line-cable. It can be determined by 40 experiment what must be the size of the weight to be suspended and the intensity of the spring or yielding connection of the weight with the line-cable for causing the greatest possible damping of the oscillation of the line.

However, the devices ard means of the kind mentioned before and known up to the present have the essential drawback that they are not free from emission and are the cause of trouble' s'as a consequence of intense point.

coronal phenomena. Therefore said devices or means can only be used for earth cables or line cables having a relatively low electrical voltage; In order to ma e fpossible the use of such devices for lines 0 higher voltage, the oscillation damper must be so arranged that emissions and discharge phe-. nomena do not occur.

For this urpose the wei ht acting as an oscillationamper is, accor ing to the present invention arranged as an annular body free from emission and the springs connecting said body with the lines are arranged within the annular body.

The present invention is represented in the drawing by various forms of construction.

Fig. 1 shows the general use of an oscillation-damper situated near to a suspension The oscillations appearing in the line a also cause a swinging movement of the damper b. The waves of oscillation of the line-cable can thereby transmit themselves freely to the oscillation-damper which acts similarly to a spring suspension of the :5 line-cable and puts at rest the largest waves as a consequence of its opposing natural vi--- bration. Thus only a few harmless oscillations can reach the suspension point '0.

An oscillation-damper free from emission and of the kind characterized above is represented by several forms in Figs. 2 to 5. Distinguishing this device from those known up to the present it will be seen that the springs forming part of said oscillation-damper and connecting the weight with the line-cable are so arranged that they are situated within a hoop-shaped rim, the edges of which are rounded in such a manner that emissions or phenomena of corona cannot .appear. Said rim has the effect of an emission or radiation-umbrella and is, at the same time, formed or shaped-as a weight proper.

The rim can be arranged in various shapes. It can be formed as a ring according to Fig. 3, or as a longitudinal cylinder, shown in Fig. 4. The main oint is that the rim completely surrounds t e springs and prevents the radiation. 7

rt, Figs. 2 to 5, is the weight to be susmo pended, shaped as a hoop, Fig. 3, or as a c linder, Fi 4. a is the lme-cable surroun ed by a sadd e or sleeve e. The springs are fastened to said sleeve and can be arranged as plate springs f, Figs. 2, 3 and 4, or as helical springs. Fig. 5. According to the constructions shown, the connection between the weight (1 and the line-cable w is not a rigid one, but the weight 4% can move itself in oscillations. The strength and the tension of the springs and the size of the weight to be suspended must be determined by ex eri ments according to the conditions 0 the line.

What I claim is:

L'An oscillation damper for electric lines comprisin an annular body and springs situated t erein for resiliently connecting a the body with the line, said body being so crnrlrlcare or CORRECTION.

Patent No. 1,766,995. r Granted June 2 4, 1930, to v JOHANNFS wrumm HOFMANN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, after line 26, insert the following as claim 3:

i p 4 3. flhe combination with a conductor of a saddle or sleeve fixed to said conductor, a rider having an opening therethrough for receiving said sleeve, said sleeve being movable in said opening and yielding means for resisting movement of' said sleeve in said opening.;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the. case in the Patent Office.-

Signed and sealed this 5th day of August, A. D. 1930.

Wm. A. Kinn'an,

(Seal) Acting Commissioner of Patents. 

